I have been using Jungle Disk for years now to transparently perform backups on multiple home computers. I have been happy because the backups went to Amazon S3, it has its own unique private key for backup, it stored multiple versions of files and I could remotely access data from multiple computers. The problem was the cost was mounting with S3 charges, I was only able to backup critical data and it did not support mobile devices.

You may say why not use cloud drives such as Dropbox as it makes files available with near real-time updates across devices. It is easy to share folders between people but the free storage is limited with shared drives costing 5-10 times what cloud backup costs. So I went on a hunt for a replacement cloud backup.

My criteria were:

500Gb of storage so I could backup all my photos and music

Able to support at least 5 computers at home – many cloud backup services are per computer

File versioning so that if a file was corrupted I could roll back to a previous version

Continuous backup at least once an hour for different file versions

Support for mobile devices including iPhone and Android

Could support a private key for encryption of my data

I spent many hours evaluating different services but either they were for a single computer (Carbonite), very slow (CrashPlan), extremely difficult to select what to backup (Bitcasa, SOS Backup, JustCloud, ZIPCloud, MyPCBackup, Backup Genie, Study Backup), did not support Android (BackBlaze) or just too expensive. Services that offered infinite storage were slow or with limited function.

Has a way of selecting backup policy both on the web and locally – good for managing laptops remotely

Is VERY fast achieving backups of 2-8GB per hour with good compression of data. Some such as CrashPlan were appallingly slow and it would take a year to backup.

You can get 5GB for free or if you are a student 25GB for free which is more than sufficient for critical coursework. There is a good review here.

Update: Just wanted to say I managed to backup 300GB of files over 3.5 days using BT Infinity 2 for 3 laptops and 2 Android devices. I test recovery of data and found it about 50% faster than backup. There are even scripts to backup from Linux and Synology NAS drives.